One assembly in a passenger vehicle is a steering wheel assembly which permits a driver to accurately steer the vehicle. Typically, the steering wheel assembly includes an upper assembly comprising a steering wheel hub mounted to a steering shaft which is enclosed in a steering wheel column. In the past, the steering wheel hub has been attached to the steering wheel shaft in a variety of ways and in most typical procedures, a fastener is used to mount the two components to one another. For example, the steering wheel hub may include a rear mounting plate having opposing sides in which an upper end of the steering wheel shaft is received at a first side. The upper end of the steering wheel shaft comprises a threaded portion which is attached to the rear mounting plate by fastening, e.g., bolting, the upper end to the rear mounting plate. This is usually done by threading a nut at a second side of the rear mounting plate to attach the two components to one another.
Most passenger vehicles have a driver's side air bag mounted to the steering wheel. The air bag assembly includes an air bag module that is disposed within the steering wheel assembly. The air bag module includes a mating connector which mates with a corresponding connector disposed at the rear mounting plate when the two are assembled. After attaching the rear mounting plate to the steering wheel shaft, the air bag module typically attaches to and mates with the second side of the rear mounting plate. The air bag module is secured to the rear mounting plate of the steering wheel by a plurality of fasteners.
During the attachment of the steering wheel hub to the steering wheel, access to the second side of the rear mounting plate is necessary so that the assembler may attach the upper end of the steering wheel shaft to the rear mounting plate by threading a bolt around the upper end of the steering wheel shaft. In another embodiment, the steering wheel assembly and the air bag assembly are partially combined and the steering wheel assembly comprises a steering wheel hub including a front mounting plate, wherein the air bag module is disposed within the steering wheel hub adjacent one side of the front mounting plate. A first connector extends from the front mounting plate and mates with a connector provided on a rear mounting plate. The rear mounting plate is attached to the upper end of the steering wheel shaft with a fastener. Next, the front and rear mounting plates mate with another and are mounted to one another via a plurality of fasteners. In this second embodiment and similar to the first steering wheel assembly, complete access to the rear mounting plate is necessary so that the assembler may receive the steering shaft on one side of the rear mounting plate and fasten the two together at a second side.
Because the steering wheel assembly typically comprises at least two components and the front and rear mounting plates are separated and not attached to one another until after the rear mounting plate is attached to the steering shaft, the overall assembly process is multi-component based which increases the time and cost to assemble the steering wheel assembly to the steering shaft.